Although electronic messaging applications (e.g., electronic mail (e-mail), instant messaging, chat applications) have revolutionized communication, in many business environments the telephone remains the predominant mode of communication. For example, trading rooms often have pressure to communicate information and receive a response over telephones in order to be as close to real time as possible and to avoid the delay introduced by most electronic communication media.
In particular, the activity in trading rooms is considered much more “peaky” than in traditional call centers. Bursts of frenzied activity can follow major events and these may last from a few seconds to a few hours. During these periods, the activity levels can be many times higher than the average load on the system. A recording system can be used in trading rooms in order to record transactions as they are occurring. Among other uses, recording systems can be helpful in recording transactions during frenzied periods of time, and should be able to perform reliably during such times. A reason for the reliability of a recording system is because during these brief “panics” traders may tend to ignore their computer systems and rely on the outcry going on around them to stay in touch. Trades are done verbally and scribbled down or remembered so that when the market calms down again, they can be entered into the computer systems. This can cause errors to arise. Thus, a recording system can help to sort out the trades that occurred.
As one example of a previous recording approach, recording capacity was connected to each trading desk rather than to the trunks entering or leaving the building. This is at least in part because the unusual topology of trading room systems (having more lines out of the building than there are desks) makes it more economical to connect recording capacity to each trading desk, and the major trading room system vendors have provided connectivity points to support such an arrangement.
Traditionally, recording systems have been priced according to the number of recording channels—which in a trading room system could all be live at once. This is because digital signal processing requirements, storage requirements, and cabling and interfacing costs have been proportional to the number of channels being recorded.
Recording systems have been developed to minimize the channels being recorded by mixing together the data streams received by each trader. This led to the development of recording systems capable of mixing up to 8 input channels into a single composite recording channel. The techniques used for this included normalizing the signals with automatic gain control, mixing and then compressing the resultant signal.
Because the mistakes and disputes that arise within a recording system can be due to over-hearing or mis-hearing, the availability and quality of the recording can be used in resolving the dispute correctly. As an illustration, in a compliance recording environment, those data streams that could have been heard and therefore acted upon are recorded. These items can include speech not originally intended for the handset/microphone that it was heard on—e.g., trader hears “Buy” and acts on it even though it was being shouted into the other handset. Also, such recording systems were used to record even the first syllable of each “call”—since this call may be just a single word, shouted to the other party. Thus, trading room peculiarities led to, among other things, recording systems which were deliberately over-sensitive and hence recorded much low level audio that may well be just background noise as well as recording the main conversation on a line. Moreover, some recording systems used look-ahead buffers which enabled the system to filter out short spikes of electrical or acoustic noise, while still recording audio longer than a few tens of milliseconds.